1. Field of the Invention
The present invention relates to a vertical conveying apparatus for conveying a large quantity of articles between facilities constructed underground at a great depth and the ground at high speed.
2. Description of the Prior Art
The use of underground spaces at great depth has been examined as a drastic measure to solve various problems posed in densely-populated areas such as large cities. In order to transport articles such as mails between a subway constructed at a depth of several tens meters and the ground, a high-speed transportation means capable of transporting a large quantity of articles is required. Since transportation is performed between positions having a great level difference, a vertical conveying means such as an elevator is suitable for this transportation means.
Elevators have been widely used as vertical conveying apparatuses. Of the elevators, elevators of a hoisting system are used for vertical conveyance of vehicles in three-dimensional parking lots.
Elevators which are used between positions having great level differences can be driven at high speed. However, since only one conveyor can be arranged in one elevator, a convey capacity per elevator is not large. Therefore, in order to transport a large quantity of articles, a large number of elevators must be installed as in a practical case.
In an elevator of a hoisting system, as used in a three-dimensional parking lot, a large number of conveyors can be arranged. However, since all the conveyors are simultaneously stopped at every time when articles are loaded or unloaded in or from one conveyor, a traveling/stopping operation must be frequently performed, and the maximum speed of the elevator is undesirably limited. In addition, since the ratio of a stopping time to a traveling time is increased, the average traveling speed is decreased. Consequently, even in this system, a convey capacity per conveyor cannot be set to be large.
In the hoisting system, when loading/unloading is to be performed, a conveying truck may be disconnected from a traveling unit so as not to stop other conveying trucks. Such a system is employed in a ropeway. If, however, this system is applied to a vertical conveying apparatus, a high-speed operation is difficult to perform, and a complicated structure is required to detachably mount a conveying truck on a traveling unit. Hence, this system is difficult to realize.
As described above, in the vertical conveying apparatuses of the conventional systems, since a convey capacity per apparatus cannot be increased, a plurality of apparatuses must be arranged to achieve a large convey capacity. In this case, a large space is occupied by the vertical conveying apparatuses, and a large excavation volume is required. Therefore, an enormous cost is required to ensure a space for installing conveying apparatuses. In addition, since a large area of the ground is also occupied, a land having a high price must be ensured at high cost.